SUBARU LEGACY 1997 Service Repair Manual

B4M0970
AD: TROUBLE CODE 52 M. RELAY ON
—MOTOR RELAY ON FAILURE—
DIAGNOSIS:

Faulty motor

Faulty motor relay

Faulty harness connector
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1255
155
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1270A
10AD1
CHECK MOTOR RELAY IN ABSCM&H/U.
Measure resistance between ABSCM&H/U terminals.
Terminals
No. 25—No. 26:
: Is the resistance more than 1 MΩ?
: Go to step10AD2.
: Replace ABSCM&H/U.
10AD2
CHECK MOTOR OPERATION.
Operate the sequence control. <Ref. to 4-4 [W20D1].>
: Can motor revolution noise (buzz) be heard
when carrying out the sequence control?
: Go to step10AD3.
: Replace ABSCM&H/U.
10AD3CHECK POOR CONTACT IN CONNEC-
TORS.
Turn ignition switch to OFF.
: Is there poor contact in connector between
hydraulic unit, relay box and ABSCM&H/U?
<Ref. to FOREWORD [T3C1].>
: Repair connector.
: Go to step10AD4.
10AD4
CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM&H/U.
: Go to step10AD5.
10AD5CHECK ANY OTHER TROUBLE CODES
APPEARANCE.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
156
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0971
AE: TROUBLE CODE 52 MOTOR
—ABNORMAL MOTOR—
DIAGNOSIS:

Faulty motor

Faulty motor relay

Faulty harness connector
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1255
157
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1256A
10AE1CHECK INPUT VOLTAGE OF
ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM&H/U.
3) Turn ignition switch to ON.
4) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 25 (+)—Chassis ground ():
: Is the voltage between 10 V and 13 V?
: Go to step10AE2.
: Repair harness/connector between battery and
ABSCM&H/U and check fuse SBF6.
B4M1257A
10AE2
CHECK GROUND CIRCUIT OF MOTOR.
1) Turn ignition switch to OFF.
2) Measure resistance between ABSCM&H/U connector
and chassis ground.
Connector & terminal
(F49) No. 26—Chassis ground:
: Is the resistance less than 0.5Ω?
: Go to step10AE3.
: Repair ABSCM&H/U ground harness.
158
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1234A
10AE3CHECK INPUT VOLTAGE OF
ABSCM&H/U.
1) Run the engine at idle.
2) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 1 (+)—Chassis ground ():
: Is the voltage between 10 V and 15 V?
: Go to step10AE4.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
B4M1243A
10AE4CHECK GROUND CIRCUIT OF
ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Measure resistance between ABSCM&H/U connector
and chassis ground.
Connector & terminal
(F49) No. 23—Chassis ground:
: Is the resistance less than 0.5Ω?
: Go to step10AE5.
: Repair ABSCM&H/U ground harness.
10AE5
CHECK MOTOR OPERATION.
Operate the sequence control. <Ref. to 4-4 [W20D1].>
NOTE:
Use the diagnosis connector to operate the sequence con-
trol.
: Can motor revolution noise (buzz) be heard
when carrying out the sequence control?
: Go to step10AE6.
: Replace hydraulic unit.
159
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

10AE6CHECK POOR CONTACT IN CONNEC-
TORS.
Turn ignition switch to OFF.
: Is there poor contact in connector between
generator, battery and ABSCM&H/U? <Ref.
to FOREWORD [T3C1].>
: Repair connector.
: Go to step10AE7.
10AE7
CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM&H/U.
: Go to step10AE8.
10AE8CHECK ANY OTHER TROUBLE CODES
APPEARANCE.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
160
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0972
AF: TROUBLE CODE 54 BLS
—ABNORMAL STOP LIGHT SWITCH—
DIAGNOSIS:

Faulty stop light switch
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1258
161
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0973
10AF1CHECK OUTPUT OF STOP LIGHT
SWITCH USING SELECT MONITOR.
1) Press [F], [0] and [9] on the select monitor.
2) Depress the brake pedal.
3) Read the stop light switch output on the select monitor
display.
: Is the reading indicated on monitor display
less than 1.5 V?
: Go to step10AF2.
: Go to step10AF3.
B4M1265
10AF2CHECK OUTPUT OF STOP LIGHT
SWITCH USING SELECT MONITOR.
1) Release the brake pedal.
2) Read the stop light switch output on the select monitor
display.
: Is the reading indicated on monitor display
between 10 V and 15 V?
: Go to step10AF5.
: Go to step10AF3.
10AF3
CHECK IF STOP LIGHTS COME ON.
Depress the brake pedal.
: Do stop lights turn on?
: Go to step10AF4.
: Repair stop lights circuit.
162
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1259A
10AF4
CHECK OPEN CIRCUIT IN HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM&H/U.
3) Depress brake pedal.
4) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 2—Chassis ground:
: Is the voltage between 10 V and 15 V?
: Go to step10AF5.
: Repair harness between stop light switch and
ABSCM&H/U connector.
10AF5CHECK POOR CONTACT IN CONNEC-
TORS.
: Is there poor contact in connector between
stop light switch and ABSCM&H/U? <Ref. to
FOREWORD [T3C1].>
: Repair connector.
: Go to step10AF6.
10AF6
CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM&H/U.
: Go to step10AF7.
10AF7CHECK ANY OTHER TROUBLE CODES
APPEARANCE.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
163
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0974
AG: TROUBLE CODE 56 G SENSOR LINE
—OPEN OR SHORT CIRCUIT OF
G SENSOR—
DIAGNOSIS:

Faulty G sensor output voltage
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1260
164
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor